Critical Safety Issues for EV, FCV and Useful Testing Machines to Solve Them

Abstract

The power train electrification has been remarkably evolving and HEVs or EVs are increasing in world-wide markets. Especially recently, pure electric driving system such as EVs or FCVs without any ICEs are highly desired as better solutions for environmental protection.

Today, discussions about EVs or FCVs are excessively biased and focused on electrical performance issues. Performance of batteries, available EV driving distance, required battery charging time, performance of fuel cells, etc. These issues are certainly important issues for EVs or FCVs development. However, there remains still other critical issues for EVs or FCVs to assure safety of vehicle driving. Discussions about safety are insufficient. Especially in mechanical field. In the long history of ICE based vehicle usage, automotive engineers have found a lot of situations and conditions for which vehicle reliability or safety should be tested and evaluated. Critical issues often come from “very rare case in market usage”, however, for such “rare case”, various kind of preparations to keep reliability and safety has adopted for vehicle reliability and safety. ICE based vehicles has long enough history to adopt various countermeasure for those “very rare case incidents”.

The author has recently found several critical issues for EVs or FCVs. In this paper, such newly found critical issues particularly for EVs or FCVs are introduced, and good way and good testing machines to develop countermeasures to solve those issues are also described. There are two important critical safety issues. One is fade risk of friction brake when EV or FCV is started from high altitude place with full SOC (State of Charge) and then driven on steep, long downhill road. To keep safety downhill driving, newly proposed Down Hill Brake (Hereafter DHB) is also introduced. Another issue is vehicle fire risk by electric devices breakage during frequent rough road or uneven road driving.

These two issues are not so critical for conventional ICE based vehicle. We should solve such particularly dedicated critical issues for EVs or FCVs earlier, because, to establish good solution for such EVs or FCVs dedicated critical safety issues earlier is inevitable hurdle to overcome for EVs or FCVs popularization.